Printing-telegraph-exchange system



Dec. 15 l, l925 1,565,343'

G. S. VERNAM ET AL PRINTING TELEGRAPH EXCHANGE SYSTEM Filed Nov.- lO, 1925 2 Sheets-Sheet l parures on llfh.

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y, `uNrrEn AsT.'ulua'sl "PATENT oFFl-CE.

. GILBERT' s. vnnNAur, or 'RIVER EDGE,` NEW JERSEY, AND DONALD E? minar, or YoNKERs', NEwHYonx, AssrGNons rro AMERICAN TELEPHQNE. AND v'rELEcraArfH "corvi-rana?, A conronA'rIoN 0E NEW YORK.

" v PRIN'RING-TEILE]GRA?Iii-EXCHANGE SYSTEM.-

Application liled November 10, 1923. Serial' o. 674,009.

To aZZaowm t may concern:

Be i-t known that we, GrLBERT- S. VERNAM and DONALD B. PERRY, residing at River Edge and Yonkers', in the counties of Bergen and Vifestchester and States of New Jersey ing telegraph exchange systems.

An object of the invention is a printing telegraph system which is Hexible and one 4'wherein a printing telegraph subscriber located in one city may extend his line automatically to a subscriber located in a distant city. v

In accordance with the preferred form oi the invention, it contemplates a-plurality of printing telegraph stations located at remote cities which are connected by a plurality ofy telegraph lines and which have located thereat machine switching apparatus' for automatically establishing a connection f between a calling and a called subscriber.

Referring to the drawings, a complete system is shown diagrammatically vwhen Figures 1 and 2 are placed end for end with Fig. 1 to the left of Fig. 2. In the drawings there are shown Atwo printing .tele raph stationsmA and B whose lines F and respectivelyextend to central offices-where suitable machine switching apparatus is located. At thc oice in which the line F terminates, there is arranged a line'switchC and a selector switch D which serveto extend the line Fito one of a plurality of telegraph lines such as 5 which extend between New York and Boston, or -any other desired city, and which vas illustrated, iS provided with duplex equipment.- As will be described hereinafter, the telegraph lines extending between the two cities are, however, not capable of the simultaneous transmission irr both directions but` are arranged for giving what is lcommonly referred to as half duplex service. Associated with the end of the telegraph line 5 terminating at the city of Boston is a connector switch E operative to connect the telegraph line l5 with the line-.cf the called for subscriber. It is understoodfeff course,I that many other lines similar to F and G extend from subscribers stations to lthe oliices at` which telegraph lines similar to 5 terminate, and so for convenience but two of Athe .lines are shown in thepresent case. Each oft-the printing telegraph subscribers stations is.

provided with an impulse sending device and lprinting telegraph equipment, the latter comprising the usual transmitter and receiving printer yfor performing their respectivev functions.'

Abetter understanding of the invention may be had from the following description,

taken in conjunction with the accompanying drawings which illustrate one -embodiment of the invention.` E

Assume for the .salie of illustration, that the subscriber A at'New York desires to communicate with. the subscriber B located at Boston.` Accordingly the subscriber A.

lrelay 24, thence over the line to the subscribers station through the transmitter and printer in series, contact 19 of the impulse sending device 22, front contact and armature'of relay 20, and over the line to the central o'tlice' and through the lowermost contact and armature of. cut-off relay 24 to ground. Line relay 28, in operating closes at its Contactr a'n operating Vcircuit for c-ut`- bff relay 24.- Cut-otf relay 24 is thereupon energized and opens ,at its lowermost contact, the operating circuit of line relay 23 and moves plunger 25 to a position where 'i contacts 17, 30 and 31 are closed. Relay 23 being ofthe slowto-release type, does not release until relayv 36 has operated as described later.

Atthe closure of contact 30, a circuit is completed for causing the' energization of line relay 35. The energizing circuit of relay 35 may be traced from battery, lefthand contact and armature of relay 58, up-

permost contact and armature of relay 43 over the line and through the transmitter and printer, contact 194` and the front conwinding of relay 35 to tact and armature of relay at station A., lcontact 31 of the line switch C, upper middle armature and contact of relay- 43, and the round. Line relay 35 in energizing, comp etes an energizingcircuit for slow-to-release relay 36 extending from grounded battery .through the winding of relay 36, front contact and armature ofV of relay 41, a locking circuit is established .relay 35 andthe lowermost armature and contact of relay 43 to ground. Relay 36 in closing its contacts, v'conditions an'energizing circuit for series relayyf( 'and thevertical magnet 38 which respndto .-the closure of thebaclr contact 'of relay 35 in response to the operation of the 'impulse sending device 22. Atithe left-hand contact and armature ofrelay 36,' there is established a locking circuit for relay 24 of the line switch CQ *i level allotted toa designated city to which y This locking circuit may be trae'd. from grounded battery, .throughj'the upper winding. of cutoff relay 24, contacts 17, and the left armature and cntact of relay 36 to ground. Asprevioiisly stated, relay 23 is o'f the slow-t'o-ielease type and remains operated after its circuit has been opened by relay 24 and until relays 35 and 3 6 have been energized to maintainrelay 24 energized after which relay/,23 releases its arma- 'tablished .at the lowermost armature and contact of relay '43, while the stepping magture.

The subscribei` A- nowpactuat'es the'im-` pulse sendingdevice 22 to send the impulses of the first digit for selecting a particular a plurality ofjtelegraph lines similar to5 are connected vand which extend between New York and Boston, thereby interrupting the circuit of line relay 35.; On the operation of the impulse sending device '22, contact 19 is 'opened thereby opening' the loop circuit. Upon the first retractionof the Aarmature ofrelay 35, a 'circuit' is com pleted from grounded battery,'switch member, 57, vertical magnet 38, series relay 37,

course, understood that these contacts 53,;54

and 55 are connected to the telegraph line 5,

there of course, being other similar contacts of this level likewise connected to otherntelegraph lines extending between the two cities.

he first upward step of the shaft on which' the wipers 50, 51 and 52 are mounted, closes the off-normal contacts 39 and 40. Through one of these contacts, an energizing circuit for the release magnet 44-is prepared, while through the other off-,normal contact, an energizing circuit for theinterrupter relay 41 is conditioned. Upon the energization of relay 37, which as previously described is energized at the Sametime as vertical magnet 38, the interrupter relay 41 will be energized over a circuit which extends from grounded battery, through the winding of relay 41, ollnormal contact 40, armature and contact of relay 37 and the left-hand armature and contact of relay 36 toground. Following the closure of the left-handcontact 35 is again yenergized thereby maintaining.

relay 36 energized. O Wingto this' operation,

the series relay 37 is deenergized closing the circuit o f stepping magnet 42. ,The energizing circuit c55-stepping magnet 42 may be, traced from 'grounded battery, through the., y winding of said magnet, right armature and4 contact"A of ,interrupter relay 41,'back contact of relay 37, andthe left-hand armature and contact of relay 36 to ground. It is to be noted here that the interrupter relay 41 depends `for its energization on the ground esnet 42 depends for its energizing -circuit. on the closure of the left-hand front contact of relay 36. The stepping magnet 42 now' operates moving the wipers 50, 51 and 52 on to' the first set of contacts such as 53, 54 and 55'." If the telegraph line which is connected to this set-of contacts is free, there will be an absence of ground on the wiper 50. However, if the telegraph line happens to be busy, there will be ay ground' on this particular contact. Assume thelatter to be the case. This ground on the'contact 53- is now connected through wiper 50 and the armature'and back contact of relay 43 to the contacts of the stepping magnet 42" and the in,

terruptcr relay 41. Near the end of' its stroke. the stepping magnet 42 opens its coninterrupter relay 41. Accordingly relay 41 is deenergized opening the energizing cirta ct, finlei'eby opening the 'locking circuit ofV cuit of stepping magnet 42. Stepping mag l net 42' closes its back-contact again closing the circuit of the' iuterrupter relay 41 to. the

wiper 50 and the contact 53. At this time," l

the interruptor relay 41 depends solely upon the wiper 50 for a circuitbecause its own circuit vto ground at the switching relay 43 is open. 'If wiper 50 rests on agrounded vcontact, the interrupter relay 41 will again energize and again cause the energization of the 'stepping magnet 42 causing itkto' rotate i the Wipers to the next set of' contacts. So

longas the wiper 50 finds ground, the interrupter relay 41 and'thestepping magnet 13 42 will vibrate.

ying of release relay 63, ,contact 53, wiper 50,l

armature, back contact and winding of switching' relay 43, operating member'65,

and thearmature and front Contact of relay -36 to ground.

The energization of switching relay 43 disconnects the line relay and extends the subscribers" line through the contacts 54 and 55 tothe telegraph line 5. It also removesv at its lowermost armature, -the ground connection through which the series relay 37 andthe verticalmagnet 38 were previously. energized, thereby preventing..

the actuation of either the series relay 37 or the vertical magnet 38 Switching relay v343 also extends the sleeve conductor through the wiper 50 and contact 53 to the lower winding of release relay 63. Prior to the deenergization of release relay 36, ground is connected to the sleeve conductor through the lowermost armature and contact of.re lease relay 63. FollowingA this operationz -release relay 36 deenergizes but the continuitycf ground on the sleeveconductor is maintained. During this operatlon,A the switching relay 43 remains energizedthere'- by holding the selector switch D in its selected position. The holding circuit for this relay mayv be traced from grounded battery, winding `of relay 41, olf-normal contact 40, back contact and armature .of magnet 42, winding of relay 43, contact and the left-hand armature and front con-4 tactv of relay 36 to ground. Relay 41 does not energize over the circuit just traced on account of the insufficiency of current.

If all of .the telegraph lines vconnected to contacts corresponding to 53, 54' and5`5 in the selected level are busy, the wiper 50 will be unable to find absencefzof ground. The wipers will therefore take eleven rotary steps. At this point in the operation,

"operating members 57 and 65 will be operated cutting off rthe switching relay 43 and the vertical magnet 38 and closing an energizing. circuit `for the busy relay 58. The

'- energizing circuit' for the busy relay 58 extends from battery, through the operating element 57v and left contactthereof, winding of busy relay 58 ofthe conducting segments of the interrupter 60 to ground. The interrupter 60 is providedwith suitable conducting and insulating segments so arranged as to effect=the transmission of impulses designatingy the character B or in some cases, it may be desired to transmit a number of groups of impulses represent'- inv theword Bus The ener ization of e y g Ythe busy relay 58 closes through its righthan'd contact and armature a circuit for release magnet 59. Thefrelease magnetr 59 controls the starting of the interrupter 60 for transmitting to the station A characlteristic` signals to indicate that the called for line: is busy. The impulses transmitted by the left-hand armature and'contact of relay 58 due to the operation of the interrupter 60 pass over the line to the subscribers station A and cause the operationi of the printer mechanism for recording a symbol which indicates that the line is busy and the calling subscriber should abandon the `call vand wait ,a few minutes before tion.

If an idletelegraph sure ofthe two uppermost` contacts of the switching relay 43, establishes a'circuit for line is seized the-cloy again attempting to establish the connecpole changer relay 62 which may be traced v from grounded battery, through the upper windingof thepole changer relay 62, upper armature and contact of control relay 61, upper armature and contact of relay 63, upper winding of relay 64, contact 55, wiper 52,. uppermost contact and armature' of switching relay 43, back over the circuit extending to the subscribers lstation A. and thence through contact 3l of the-line switch C, armature 66 and front contact of switchingvrelay 43, wiper 51;"contact-54, lower` winding of relay 64cto the opposite pole of the battery. It is t0 be noted that relay 64 is of the dierential type and does not pull up its armature upon the completion ofthe circuit just traced. Due to the establishment of the energizing circuitfor the pole changer 12'045 relay 62, the armature controlled thereby is caused to engage the contact to which the negative pole of the battery is connected for transmitting over the telegraph line ,5 v a marking impulse. This impulse upon being 'received at the other end of .the Itelegraph line 5 operates relay 67 which-in turn causes. the operation of` control relay-68. Control vrelay68 in closing its upper contact, establishes the following circuit: positive pole of battery through the upper winding of relay 70, contact 73-controlledby-relay 93, back contact and armature of relay`72, resisti'e 71, lower Winding ofrelay 70, lower 4winding of relay 69, front contact and upper armature of relay 68,- and the upper windingof pole changer relay 56ste the neg-ative lle of the battery. Relay'7 0 is not energized at this time due to the differential connection of its windings. The value of the resistance 7l -ischosen so that it equals the resistance of a normal subscribers line circuit to maintain a current of approximately 60 milliamperes flowing therein. Due to the establishment of the circuit just traced, line relay 69 is energized and establishes an energizing circuit for release relay 74 which is of the slow-to-release type.v Release relay 7 4 prepares through its innermost armature and front c. ntact the energizing circuit of the. series relay net 76.

. lv'hen the pole changer relay 62is operated in accordance with such' operation for ycausing the, transmission ol' impulses to operate receiving rela)1 67', whereby line relay' 69 vibrates its armature and establishes alternately the circuit for the release relay 74 and for vthe series relay 7 5 and vert-ical magnet 76. During the operation of relay 68 pole changer relay 56 does not' follow such operation owing to its working circuit. The releaserelay 74 remains energized but the vertical magnet 76 .is quick acting and follows the impulses' and lifts the wiper shaft upon *which the wipers 86, 87 and 88 aredmounted. The series relay operates on the first impulse and remains energized to the end ol the se`-'.

ries of impulsesimpressed on ythe vertical magnet 76. l .i

On the lirst upward movement of the wiper shaft. contact 77 is opened whilecontacts 78 and 79 are closed. The closure of Y contact 7 8'extends the energizing circuit o f the vertical magnet 76 through the armatureand front 'Contact of the series relay 75, while the closure of contact 79 prepares a circuit for the energizati'on of the release magnet 105. Inasmuch as the release `relay 74'and the series relay 75 are at this time energized, the movement of'the wiper shaft produces no changes.

When the impulses cease. line relay 69 re- 'mains energized and the Vseries relay 75 1s accordingly deenergized.` The impulse cir-` cuit is now transferred to the stepping relay 83 and thestepping magnet 84. When the "subscriber dials the last digit, the line relay 69 again vibrates sending pulsations through the stepping relay 83 and the steppingmagnet 84 in parallel. The stepping magnet 84 rotates the wipers 86. 87 and 88 over the bank ot contacts in which contacts 89, 90 and-lf 91 individual to the called for subscriber,-

are located. No interference with other connected lines 1s caused due to the movement of the wipers 86, 87 and 88 over the bank of 7 5 and the 'vertical mag' subscriber A dials the tens digit,

been received. lfhen this occurs, the stepping relay 83 will also be released and if the 'called or line is lot busy, busy relay 92 will be released duc to the absence of ground on the Contact to which wiper 86 is now cnraged.

lf the called for line is not busy, the wiper 86 on engaging contact 89 connects battery through one of the relays of th'e line switch tothe upper winding of switching rela-y 81 for causing the energization of this relay. The energizing circuit 'for the switching relay 81 maybe traced from grounded battery at the liuc switch, contact 89, wiper 86, righthand :nature and contact of relay 83, upper winding of relay 81, uppermost contact and armaturcof busy relay 92 and the outermost armature and contact of relay 74 to ground. Following the closure of the .con-

tacts of the switching relay 81, a locking circuit therefor is established from grounde .u

and front contact thereof, and the left-haid' armature and front contact of relay 74 to ground. Ground is also'connected to the wiper 86 dueto the energization of. the switching relay 81 making the called for line busy. Relay 81 also vopens the circuit of the stepping magnet 84 and of the busy relay 92.

The wipers 87 and 88 are now closed through to the ringing c u't-o relay 93 an'd ringing current will be transmitted intermittently through the upper Winding of ringing cut-oli relay 93 andover the ring side of the line through the callbell 96 and as-A sociated condenser to ground. The ringing cut-ofi' relay 93 is designed so that it' will not operate on the alternating ringing current but when the subscriber B responds to' the call-by the operation of switch 101v battery through the lower winding, armatnre 1 j which corresponds to switch 18 at'station A, the disconnection of the call bell 96 and the'completion of the circuit through the front contact of relay 102 permits direct curno vrent to flow through the upper winding of ringing cut-oil' relay 93 to effect this operation. Ringing cut-off relay 93 in operating disconnects the source'of ringing current rom'the line and establishes alocking circuit for itself extending from grounded batgtery, through the front contact and armature thereof, and the left-hand armature and "front contact of relay 74, to ground. It also removes the ground connection from the tip conductorand disconnects the resistance 71 from. in bridge of the signaling circuit. A locking circuit is also completed for relay '69 upon the energization of ringing cut-oli relay 93. Relay 69 is thus prevented from following the printed signals and causing theff'false-release of the switching mechanism. l

A channel of communication is now establshed between vthe subscriber A located c vise ksuch subscriber of the completion of the connection and that the subscriber B is in readiness to receive any messages which the. subscriber A may desire to transmiti' Should the called for subscribers line be fbusy, busy relay 92 will be energized over a circuit completed through the wiper 86 and the contact 89 to ground at the line switch. Busy relay 92 opens at its back contactl the energizing circuit of switching relay 81 thereby preventing the energization of this relay. Busy relay 92 on the release ot' relay 83`will be locked up`=0ver a circuit extending through its upper iront contact and the right-hand armature and contact of relay 74 to ground. Likewise the energizing circuit or' the stepping relay 83 is opened and consequently any subsequent energizationof this relay by further dial impulse or printer signals from the calling station is prevented. There is also completed due to the energization of the busy relay 92 an`y en- 'ergizing circuit for the release magnet 99 of the interrupter 100 which is similar to that described in connection with the interrupter 60 and which controls the'energization ot'- relay- 72. On-the operation of 'the' interrupter' 100, relay 7,2 is caused to open and close its contacts in accordance with the conducting and insulating segments on the interrupter 100and accordingly opening the line ,circuit foreftecting the operation of the pole changer relay 56. The pole changer relay 56 re-` sponds to the operation of relay 72 and transmits over the tele aph line 5 impulses which elect the operatlon of `receiving relay 106. The receiving relay 106 controls the energization of control relay 61 which/in responding tothe operation of this relay, causes the transmission of impulses to the subscribers station )A corresponding to those transmitted dueto the operation of the interrupterf100. Accordingly,the vprinter at the subscribers station A will be operated for giving a printer record that the called for subscribers line is bus a that thcall should"be abandoned for the time being.

When the transmission of messages b'etween the connectedstations' has been completed, therelease of the switching mecha,- nism is controlled jointly by both stations. lf the called subscriber disconnects his printer equipment rst'by the 'opening of switch 101, the differential relay '103 will be operated over the tip sideof- 'the loopacircuit.l Dierential relayv 103` in energizing opens the locking circuit of line relay 69 and connects the resistance'104 circuit i with the winding ot the pole changer relay.'

56, whereby the pole changer and the line relay 69 are maintained energized over a circuit extending from battery, through thel upper Winding of .polechanger relay 56,

the position shown in the drawing for effect-i y ing the transmission of a spacing impulse and the corresponding operation of receiving relay, 67. Gonsequently,' control relay 68 is deenergized whereupon line'relay 69 releases its armature followed after a short interval by the deenergization of release relay. 74. Switching relay 81 releases quickly opening the line wipers and removing the ground from the wiper 86. Release magnet 105 willnow be energized over .a circu'it extending from battery, through the winding of release magnet 105, oitnormal contact 79, back contact and innermost armature of relay 74, back contact and armature of relay 69 to ground. .The release magnet 105 will restore the 'switch mechanism E to its normal condition. The ringing cut-off relay 93 is vslower to release than the switchin relay 81 so that the wipers 87 and 88 wi l not have, any ringing current on them while they are rotating to their normal position.

If the subscriber A`disconnectsv first, the line switch C vand the switch mechanism D will release, but the switch mechanism E will not 4release as the line relay 69 will remain locked up through the baclr'contact of differential relay 103 and the front contact of ringing cut-oli relay 93. VVhenasubscriber A disconnects the transmitter and receiving-printer by opening switch 18 thereby causing the deenergization of relay 20 and the closure of its back contact, an energizing'oircuit "is established for differential relay 64. This relay, in operating,

.opens the holding circuit of relay 63 and the switching relay 43. The latter relay in releasing its armature, closes at its lowerm'ost armature and back contacta circuitfor release magnet 44 which may be traced from grounded battery winding of release magnet 44, oli-normal -contact 39, right-hand `back contact and armature of relay' 63, back 'one of a plurality of printing telegraph subscribers located in distant cities. However, when the called subscriber disconnects, the differential relay 103 is energized and effects the release of line relay 69 which as previously described controls .the ehergizatiqn of release magnet 105 for restoring the switch mechanism E to normal.

vAlthough the invention has been disclosed with reference to a' particular type'of System, it is obvious that various modifications may be made without departingA from the spirit and scope of the present invention.

What is claimed is: f i l. In a telegraph system, a plurality of printing telegraph stations locatedat distant cities, printing telegraph and impulse sending devices at each of the stations, fa plurality lof telegraph lines extending between said cities, machine switching apparatus responsive to the operation of said impulse sending device for seizing one. of said telegraph lines, machine switching apparatusat the other -end of said line, means responsive tothe seizure of said telegraph line for seno'- ing a preliminary impulse thereoverto condition said second mentioned machine. switching apparatus for operation, and

.means operated due to the further operation I to the calling station characteristic impulses for operating the printing telegraph apparatus thereat to record the busy condition of .the telegraph lines.

3. In vva telegraph system, a plurality of printing telegraph stations located at distant cities. printing telegraph and impulse sending devices at each of the stations, a plurality of telegraph lines extending betweenl said cities, machine switching. apparatus responsive to the operation of said impulse sending device for seizing one of said telegraph lines,l and start-stop interrupter means eifectiveupon the failure of saiol ma.- chine switching apparatus to seize one of said telegraph lines for transmitting to the calling station characteristic impulses to' effect the operation of the printing telegraph apparatus' thereat to record the busy condition of saidtelegraph lines. u

4. In a. telegraph system, a plurality 'of stations, number of central otlices having automaticswitches therein, telegraph lines interconnecting said offices and appearing in said switches, each of said lines comprising a single conductor, printing and impulse sending devices at each of said stations, said switchesbeing responsive to said impulse devices for selecting 'a telegraph line, and means responsive to one-of said switches when all lines are found busy for sending signals toa calling station to operate the printing device thereat. y

5. In a telegraph system, aplurality of stations each having a printing device thereat, a central oiHce, aplurality'of telegraph*l lines outgoing froms'aid oflice, automatic switches in said Qiiice for connecting said stations to sai-Cl telegraph lines," means at said stations for operating said switches to select a group of said lines, and an inter-' `rupter associated with said switches and responsive to one of said switches when all desired lines are found busy-'for transmitting signals tothe calling station to operate the I printing device thereat.

6. In a telegraph system, a plurality.y

printing telegraph stationsA located atdisltant points, printing and vimpulse sending` devices at each of said stations` a plurality of telegraph lines,.an automatic switch controlled by`said impulse devices for'selecting said lines to establish a connectionfbetween two of said Stations, release means for said switch, a differential relay having two windings for controlling theV operation of said release means, said relayfbeing included in said lines in such a manner as not to re` spond to the opening thereof when telegraph signals are being sent, and means controlled from said stations for causing said relay to operate.

In testimony whereof, we liavesigned our names to this specification this18th` day of November, 1923.

GILBERT s. vERNAM. ,i 'I

DONALD n runny. 

